[Bug c++/18545] New: [3.4/4.0 regression] ICE when returning undefined type

["reichelt at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

The following invalid code snippet crashes the C++ frontend:

===================================================
struct A;

A foo()
{
    A a;
    return a;
}
===================================================

bug.cc: In function 'A foo()':
bug.cc:7: error: return type 'struct A' is incomplete
bug.cc:9: error: aggregate 'A a' has incomplete type and cannot be defined
bug.cc:10: internal compiler error: tree check: expected class 'type', have
'exceptional' (error_mark) in check_return_expr, at cp/typeck.c:6296
Please submit a full bug report, [etc.]

The bug is present since gcc 3.4.0.
Looks like it was introduced with the new parser:
: Search converges between 2002-12-14-trunk (#159) and 2002-12-29-trunk (#160).

-- 
           Summary: [3.4/4.0 regression] ICE when returning undefined type
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Keywords: ice-on-invalid-code, error-recovery, monitored
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: reichelt at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18545